期刊文献+
共找到3篇文章
< 1 >
每页显示 20 50 100
钒氧阴离子团簇与小分子碳氢化合物反应的实验和理论研究(英文) 被引量:8
1
作者 马嘉璧 吴晓楠 +2 位作者 赵艳霞 何圣贵 丁迅雷 《物理化学学报》 SCIE CAS CSCD 北大核心 2010年第7期1761-1767,共7页
为了在分子层次上揭示相关催化反应的机理,人们对过渡金属氧化物团簇与碳氢化合物分子反应进行了大量研究.相比于过渡金属氧化物团簇阳离子,阴离子对一些碳氢化合物的活性弱得多,因此研究还很少.在本工作中,我们通过激光溅射产生钒氧团... 为了在分子层次上揭示相关催化反应的机理,人们对过渡金属氧化物团簇与碳氢化合物分子反应进行了大量研究.相比于过渡金属氧化物团簇阳离子,阴离子对一些碳氢化合物的活性弱得多,因此研究还很少.在本工作中,我们通过激光溅射产生钒氧团簇阴离子VxOy-,产生的团簇在接近热碰撞条件下与烷烃(C2H6和C4H10)以及烯烃(C2H4和C3H6)在一个快速流动反应管中进行反应,飞行时间质谱用来检测反应前后的团簇分布.在VxOy-与烷烃的反应中,生成了产物V2O6H-和V4O11H-;在与烯烃的反应中,产生了相应的吸附产物V4O11X-(X=C2H4或C3H6).密度泛函理论计算表明:V2O6-和V4O1-1可以活化烷烃(C2H6和C4H10)的C-H键,也可以与烯烃(C2H4和C3H6)发生3+2环化加成反应形成一个五元环结构(-V-O-C-C-O-),C-H键活化与环加成反应都需经历可以克服的反应能垒.理论计算与实验观测结果相符合.V2O6-和V4O1-1团簇都具有氧原子自由基(O·或O-)的成键特征,活性O-物种也经常出现在钒氧催化剂表面,因而本研究在分子水平上,揭示了表面活性氧物种与碳氢化合物反应的机理. 展开更多
关键词 密度泛函理论 钒氧团簇 飞行时间质谱 C—H键活化 多相催化
下载PDF
Photodissociation and Density Functional Calculations of Small VmOn+ Clusters
2
作者 李仁忠 许洪光 +2 位作者 曹国进 赵雨超 郑卫军 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2011年第5期572-579,I0004,共9页
Oxygen-poor vanadium oxide clusters, V2On+ (n=l, 2), V3On+ (n=l, 2, 3), and V4O3+, were produced by laser vaporization and were mass-selected and photodissociated with 532 and 266 nm photons. The geometric stru... Oxygen-poor vanadium oxide clusters, V2On+ (n=l, 2), V3On+ (n=l, 2, 3), and V4O3+, were produced by laser vaporization and were mass-selected and photodissociated with 532 and 266 nm photons. The geometric structures and possible dissociation channels of these clusters were determined based on the comparison of density functional calculations and pho- todissociation experiments. The experiments show that the dissociation of V2O+, V2O2+, and V3O3+ mainly occurs by loss of VO, while the dissociation of V3O+ and V4O3+ mainly occurs by loss of V atom. For the dissociation of V3O2+, the VO loss channel is slightly dominant compared to the V loss channel. The combination of experimental results and theoretical calculations suggests that the V loss channels of V3O+ and V4O3+ are single photon processes at both 532 and 266 nm. The VO loss channels of V2O2+ and V3O3+ are multiple-photon processes at both 532 and 266 nm. 展开更多
关键词 Mass spectrometry Mass-selection PHOTODISSOCIATION Vanadium oxide cluster
下载PDF
Hydrothermal Synthesis and Crystal Structure of [H_4As_8V_(14)O_(42)(H_2O)]·6H_2O
3
作者 崔小兵 徐吉庆 +3 位作者 李光华 施展 丁红 杨国昱 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2004年第10期1138-1142,共5页
The title compound [H4As8V14O42(H2O)]6H2O 1 has been synthesized and characterized by elemental analysis, IR, and single-crystal X-ray diffraction analysis. It crystallizes in trigonal, space group R3c with a = b = 36... The title compound [H4As8V14O42(H2O)]6H2O 1 has been synthesized and characterized by elemental analysis, IR, and single-crystal X-ray diffraction analysis. It crystallizes in trigonal, space group R3c with a = b = 36.447(6), c = 21.485(5) ? V = 24717(8) 3, Z = 18, Mr = 2114.66, Dc = 2.557g/cm3, F(000) = 17928, m = 7.149 mm-1, R = 0.0792 and wR = 0.1265. The [H4As8V14O42- (H2O)] cluster consists of fourteen VO5 square pyramids linked by four As2O5 handle-like units. 展开更多
关键词 hydrothermal synthesis POLYOXOMETALATE arsenic-vanadium cluster hydrogen bond crystal structure
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部